As used herein, the term "regular geometric shape" refers to the common two-dimensional shapes of a rectangle, square, oval, circle, triangle or other similar ordinary shape.
Thin distribution flow plates having complex distribution flow patterns formed on one surface thereof accompanied by through holes are known. Distribution flow plates of that type improve flexibility and melt flow processing when compared to the state of the art at the time of that invention. Such plates are disclosed in co-owned U.S. Pat. No. 5,162,074 issued Nov. 10, 1992, "Profiled Multi-Component Fibers and Method and Apparatus for Making Same".
Although thin distribution flow plates having complex flow patterns provide many advantages, additional advantages are available when the multiple functions of these thin plates are split up so that only a single function is performed in a single thin plate. This allows mixing and matching of functions by interchanging only one or more of the single function plates within a stack of plates. For example, by changing one or more of the single function plates, the resulting fiber's cross-section can be changed from sheath/core to side-by-side without modification of the other spin pack parts.
French Patent No. 2,429,274 discloses a stack of thin plates useable to combine distinct polymer streams prior to the backhole of a spinneret. Each backhole requires its own stack of plates although the stacks may be interconnected. Because they result in polymer stream mixing, these plates are unsuitable for forming many cross-sections, for example, sheath core.